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Development of framework for the manufacture of customized titanium cervical cage implants using additive manufacturing

Marcantonio, Graziano (2014-04)

Thesis (MEng)--Stellenbosch University, 2014.

Thesis

ENGLISH ABSTRACT: Neck pain is a common phenomenon that occurs in a large percentage of the
population every day. While many occurrences are not deemed critical such
as those from muscle strain which can be treated with rest and pain medication,
others due to sports injuries, whiplash from car accidents, bad posture or
degeneration of the intervertebral disc can be quite severe. In extreme cases
failure of the vertebra(e) or the intervertebral disc requires surgery and possibly
the use of cervical implants.
Where intervertebral discs fail due to herniation or Degenerative Disc Disease
(DDD), Anterior Cervical Discectomy and Fusion (ACDF) is a common surgical
method used to remove the a ected disc and replace it with a cervical
cage implant. These implants are designed to restore the height between the
vertebrae, allowing bone from both vertebrae to grow through them and mineralise.
Additive Manufacturing (AM) technologies can produce parts with
complex geometries not possible using conventional manufacturing methods.
This design freedom, coupled with CT scans of a patient, allow for tailoring an
implant to the speci c anatomy of the a ected vertebrae using CAD software.
Such an approach must be regulated and shown to be technically and commercially
feasible before it can be implemented in industry. This study sought to
develop a framework for manufacturing customized cervical cage implants using
additive manufacturing. The e cacy of customization to reduce the risk of
subsidence was investigated by means of non-destructive and destructive mechanical
testing on six cadaver specimens, using readily available PEEK cage
implants as a benchmark. The results showed that the customized implant was
comparable to the PEEK, with no statistically signi cant di erence between
the two. In extreme cases, where PEEK implants cannot be used, customized
implants could be a suitable alternative to reduce the risk of subsidence.
A manufacturing cost analysis was conducted to determine economic feasibility.
The estimated cost and selling price of the customized implants under
various utilization scenarios and mark-ups was compared to readily available
PEEK implants. The estimated selling prices of the customized implants compared
favourably to the PEEK verifying the economic viability of using AM.